In the testing of hardness of materials, various types of jigs are used to hold a hardness testing device in proper relationship with the surface whose hardness is to be tested. Such a jig might include a drill press or other well-known tool holding apparatus which permit the testing device to be positioned perpendicularly to the surface being tested and to apply a preselected force to the test surface through an indentor, such as a steel ball, diamond, or point. The use of conventional jigs for holding testing devices generally do not permit the convenient positioning of the testing device in proper relation to a surface to be tested when the surface is other than a planar surface, as for example inside and outside surfaces of a pipe, weld material at the juncture of plates arranged at 90.degree. to each other, and other convex and concave configurations.